<html><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">I think most of the questions are very reasonable. But it seems that we HAVE to have a reasonable plot for the double moments. <div><br></div><div>Lei<br><div><br><div>Begin forwarded message:</div><br class="Apple-interchange-newline"><blockquote type="cite"><div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><font face="Helvetica" size="3" color="#000000" style="font: 12.0px Helvetica; color: #000000"><b>From: </b></font><font face="Helvetica" size="3" style="font: 12.0px Helvetica">Diego Bettoni <<a href="mailto:bettoni@fe.infn.it">bettoni@fe.infn.it</a>></font></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><font face="Helvetica" size="3" color="#000000" style="font: 12.0px Helvetica; color: #000000"><b>Date: </b></font><font face="Helvetica" size="3" style="font: 12.0px Helvetica">June 12, 2012 8:26:25 AM EDT</font></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><font face="Helvetica" size="3" color="#000000" style="font: 12.0px Helvetica; color: #000000"><b>To: </b></font><font face="Helvetica" size="3" style="font: 12.0px Helvetica"><<a href="mailto:lei.guo1@fiu.edu">lei.guo1@fiu.edu</a>></font></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><font face="Helvetica" size="3" color="#000000" style="font: 12.0px Helvetica; color: #000000"><b>Cc: </b></font><font face="Helvetica" size="3" style="font: 12.0px Helvetica">Reinhard Beck <<a href="mailto:beck@hiskp.uni-bonn.de">beck@hiskp.uni-bonn.de</a>>, "Naomi C.R. Makins" <<a href="mailto:makins@uiuc.edu">makins@uiuc.edu</a>></font></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><font face="Helvetica" size="3" color="#000000" style="font: 12.0px Helvetica; color: #000000"><b>Subject: </b></font><font face="Helvetica" size="3" style="font: 12.0px Helvetica"><b>PR12-12-008</b></font></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><br></div> </div><div>Dear Guo,<br> I am one of the readers of the proposal PR12-12-008 to be discussed at PAC39 and I have a few comments questions at this time. Here they are, in no particular order.<br><br>1. The Theory TAC raised some serious questions about the way the proposal is written and also about the contents. Please make sure that all these questions are addressed before the PAC presentation next tuesday. In particular the question of the u/d mass difference, about which the theory reviewers seem to disagree about the way you plan to measure it from the data.<br><br>2. It is not clear to me what physics conclusions can be drawn from the measurement of the photoproduction cross section. As you point out the four predictions in Fig. 15 are all consistent with each other, so it is not clear to me how effective the measurements will be in distinguishing between the various models, with the exception of the dashed red curve (by the way, what model does it correspond to ? Is it the VMD calculation ?). Also if I look at Fig. 18, which shows calculations for various cascade production channels, I note that for the only channel for which there are experimental data they agree pretty well with the theory calculation: what are you expecting to find when you measure the other channels ?<br><br>3. What level of simulation was used in the estimation of backgrounds (pp. 41-43) ? You mention fast simulation (with parametrized detector response): was a full event reconstruction performed or was the Monte Carlo truth used in the background estimations ? Is a full simulation foreseen ?<br><br>4. For the determination of the spin/parity quantum numbers (which is a crucial measurements if one aims at having a complete picture of the cascade spectrum) the DMA method is illustrated, but there is no quantitative discussion of the actual number of events needed to make this measurement in CLAS12, beyond the rather generic statement that large statistics will be collected in the relevant cascade production channels. I think that this measurement proposal should be supported by a more quantitative discussion and possibly a full simulation to demonstrate its feasibility in CLAS12. Also: have other methods to measure J^P been considered ? (e.g. Dalitz analysis).<br><br>5. Is there another advantage in the increased photon energy, beyond the broader kinematical range mentioned at several points in the proposal ? (e.g. observables which have a significant dependance on the photon energy).<br><br>6. A minor point: on page 12 you write that "it seems plausible that the one NA48 high-statistics measurement of the Csi_0 mass could be too low". Why is that so ? Since it is the only high-statistics measurement isn't it plausible that it be the most reliable ?<br><br>7. Do I understand correctly that this proposal does not impose any further requirements on the CLAS12 detector ?<br><br>This is all for the moment. I am looking forward to your presentation at the PAC next tuesday.<br><br>best regards<br>diego<br><br><br>-- <br><br>Diego Bettoni<br>INFN Ferrara, Director<br>Via Saragat, 1<br>I-44100 FERRARA<br><br>tel: +39-0532-974275<br>tel: +39-0532-974332<br>fax: +39-0532-974300<br><br>web: <a href="http://www.fe.infn.it/~bettoni/">http://www.fe.infn.it/~bettoni/</a><br><br></div></blockquote></div><br></div></body></html>